Condensed-Matter Physics & Materials Science Seminar

"“From simplicity to complex in high temperature superconductivity: imaging multiscale phase separation in a cuprate in a non-equibrium state""

Presented by Antonio Bianconi, Sapienza University of Rome, Italy

Thursday, February 23, 2012, 11:00 am — Bldg. 480 conference room

From the beginning of the last century, all conventional superconductors have been supposed to be simple and homogeneous systems. At the time of this abstract, all high temperature superconductors are more and more recognized to be complex materials and also far from thermodynamic equilibrium. Here we report that the ordering of oxygen interstitials in>the La2O2+y spacer layers of La2CuO4+y high-Tc superconductors is characterized by a fractal distribution up to a maximum limiting size of 400 μm. Intriguingly, these fractal distributions of dopants seem to enhance superconductivity at high temperature. The time resolved evolution of the defects nucleation, growth and organization have been investigated by x-ray diffraction under continuous x-ray illumination. The new insight in the complexity of the well-known superconducting material La2CuO4+y has allowed us to understand and demonstrate some necessary steps to 'write' superconducting wires on the micrometre scale.

References

1. N. Poccia, M. Fratini, A. Ricci , G. Campi, L. Barba, A.
Vittorini-Orgeas, G. Bianconi, G. Aeppli and A. Bianconi,
“Evolution and control of oxygen order in a cuprate superconductor”
Nature Materials 10, 726 (2011)

2. M. Fratini, N. Poccia, A. Ricci, G. Campi, M. Burghammer, G.
Aeppli, and A. Bianconi,
“Scale-free structural organization of oxygen
interstitials in La2CuO4+y”
Nature 466, 841 (2010),

Hosted by: Ivan Bozovic

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